Haven't seen this posted yet....so.

Symantec Corp. is warning its customers about a security vulnerability within its antivirus application. The Internet security vendor ranks the flaw as "medium," while security research group Secunia pegged the flaw as "moderately critical."

The flaw, which resides within Symantec's Norton AntiVirus 2004 application, could let attackers run code of their choice on a user's system, launch unauthorized pop-ups, or even create a denial-of-service condition to freeze Symantec's antivirus application. Virus and worm writers are increasingly attempting to disable antivirus and personal firewall security applications, so a flaw such as this would be a prime target for virus writers seeking to disable a user's defenses.
It's the second time this month that Symantec users have been advised to patch their security applications. On May 12, Symantec posted a security advisory and a handful of patches to fix several flaws within its consumer and corporate security software. Those flaws affected the consumer versions of Norton AntiSpam, Norton Internet Security and Professional, as well as Norton Personal Firewall for the years 2002 through 2004. Security holes within Symantec's corporate security software, Symantec Client Firewall 5.01 and 5.1.1 and Symantec Client Security 1.0, 1.1, and 2.0 also were disclosed.
Source